Self-threading needle

ABSTRACT

A sewing machine is disclosed in which a threading slot is provided along the needle blade and opening into the needle eye. This needle, which may be fabricated using conventional milling and grinding machinery, provides a self-threading needle eye construction which will deter re-entry of the thread into the threading slot once the thread has been drawn into the needle eye.

United States Patent Ketterer [s41 SELFQTHREADING NEEDLE [4 1 Oct. 24,1972 2,178,607 11/1939 Rainville ..l12/224 2,273,592 2/ 1942 Rainville..1 12/224 2,539,859 l/195l Rainville ..1 12/224 2,767,670 10/ 1956Surbeck ..1 12/ 224 Primary Exantiner-Wemer l-l. SchroederAttorney-Marshall J. Breen et a1.

[57] ABSTRACT A sewing machine is disclosed in which a threading slot isprovided along the needle blade and opening into the needle eye. Thisneedle, which may be fabricated using conventional milling and grindingmachinery, provides a self-threading needle eye construction which willdeter re-entry of the thread into the threading slot once the thread hasbeen drawn into the needle eye.

4 Claims, 7 Drawing Figures SELF-THREADING NEEDLE BACKGROUND OF THEINVENTION under certain sewing conditions the thread can re-enter thethreading slot and escape from the needle eye.

BRIEF SUMMARY OF THIS INVENTION It is an object of-this invention toprovide a selfthreading sewing machine needle which includes a threadingslot extending along the needle blade and opening into the needle eye,which can be manufactured using conventional milling and grindingmachinery, and which will provide a needle eye construction into whichthe thread once introduced is deterred from being drawn back up thethreading slot during sewing operations.

These objects of this invention are attained by a needle construction inwhich a groove of uniform cross sectional configuration is milledlengthwise along the needle blade, and a resilient tongue attached as bywelding to the point of the needle is constrained in the groove. The eyeof the needle is formed by an outwardly open transverse notch formed inthe needle blade and a contiguous inwardly open transverse notch formedin the resilient tongue. By making the notch in the needle bladeshallower than the lengthwise groove, the thread once in the needle eyewill be prevented from re-ent'ering the threading slot from the inside,and by forming the notch in the needle blade so as to extend closer tothe needle shank than the notch in the resilient tongue, the thread willtraverse the abutting edges of the needle blade and the resilient tongueat such a flat angle regardless of the direction of sewing that thethread cannot be drawn into the threading slot from the outside.

DESCRIPTIONOF THE DRAWINGS FIG. 1 represents an elevational view of asewing machine needle embodying this invention as viewed from a positionlooking through the needle eye,

FIG. 2 represents an elevational view taken from the right-hand side ofthe needle of FIG. 1,

FIG. 3 is an enlarged cross sectional view of the needle takensubstantially along line 3-3 of FIG. 1,

FIG. 4 is an enlarged cross sectional view of the needle takensubstantially along line 4-4 of FIG. 1,

FIG. 5 is an enlarged cross sectional view of a modified form of theneedle taken substantially along line 44 of FIG. 1,

FIG. 6 is an enlarged perspective view of a fragment of the needle ofFIGS. 1 and 2 in the vicinity of the needle eye and showing a threadloop passing through the needle eye, and

FIG. 7 is an elevational view of that portion of the needle shown inFIG. 6, including the thread loop passing through the needle eye.

As illustrated in the drawing, the needle of this invention is formedwith a cylindrical shank 11 which may be slabbed as at 12 fororientation in a sewing machine needle clamp. From the shank, the needletapers to a cylindrical blade portion 13 which at the opposite end fromthe shank is formed with a pointed extremity 14.

The needle blade is formed lengthwise with a groove 15 of uniform crosssectional shape extending from the pointed extremity 14 to the needleshank 11. As shown in FIGS. 3 and 6, the groove 15 is preferably formedby a rotary milling cutter and includes a bottom wall 16 and a side wall17 extending at right angles to the bottom wall. Preferably, the bottomwall 16 of the groove l5 includes a recessed portion 18 adjacent to theside wall 17. The groove 15 occupies approximately one quadrant of thecross sectional area ofv the cylindrical needle blade 13 and defines aforwardlyv extending fin 19 of the needle blade which also comprisessubstantially a quadrant of the needle cross section.

A resilient tongue 30 preferably of uniform rectangular cross sectionalshape is arranged in the groove 15. The tongue 30 includes one flat sidewall 31 arranged contiguous to the side wall 17 of the groove 15. Thetongue also includes an inside edge 32 extending within the recess 18and an outside edge 33 substantially flush with the front edge of thefin 19 on the needle blade. The tongue 30 extends from the pointedextremity 14 to the needle shank 1 1 and at the needle shank, the tongueterminates in an inclined extremity 34. The needle shank is formed witha shallow transverse notch 35 which exposes the tip of theinclinedextremity 34 of the tongue to provide for introduction of threadthereto as is shown in FIGS. 1 and 2.

As shown in the drawings the resilient tongue 30 is formed with atransverse notch 40 which defines the needle eye. The notch 40 is opento the inside edge 32 of the tongue which extends into the recess 18 inthe bottom wall of the groove 15. The resilient tongue 30 is secured tothe needle blade as by a weld from the lower wall 41 of the notch 40 tothe pointed extremity 14 of the needle. Above the upper wall 42 of thenotch 40, the resilient tongue is not attached to the needle blade andthus when the thread is introduced between the needle blade and thetongue as shown in FIGS. 1 and 2, it may be drawn downwardly between thetongue and the needle blade into the notch '40 in the tongue 30 whichdefines the needle eye.

The fin 19 of the needle blade is formed with a transverse notch 50disposed opposite the notch 40 in the resilient tongue. The bottom wall51 of the notch 50 is preferably flush with the bottom wall 16 of thegroove 15 and proud of the recess 18 as shown in FIG. 4 thus providingfor an overlapping relation with the inside edge 32 of the tongue sothat the thread once drawn into the notch 40 in the resilient tongue 30will be prevented from escaping out of the notch 40 in the direction ofthe bottom wall 16 of the groove 15.

FIG. 5 illustrates a modification of the shape of the groove 15 and theshape of the notch 50 in which the groove 15 is formed without therecessed portion 18. With this modified arrangement, in order to providefor an overlapping relation of the inside edge of the tongue 30 by theneedle blade to prevent egress of thread from the notch 40 in thedirection of the bottom wall 16 of the groove, the notch 50 is madeshallower than the bottom wall 16 of the groove 15, Therefore, in themodification shown in FIG. 5, the bottom wall 51' of the notch 50 isproud of the bottom wall 16 of the the lower wall 52 of the notch 50 inthe fin 19 is disposed substantially coplanar with the lower wall 41 ofthe notch 40 in the resilienttongue 30. The upper wall 53 of the notch50, however, is spaced considerably above the notch 40. As indicated inFIG. 7 the notch 50 is preferably formed at least twice the dimensionlengthwise of the needle blade in comparison with the notch 40 and as aresult, a limb of thread Tw extending from the notch 40 will be inclinedabout the upper wall 53 of the notch 50 at an obtuse angle asshown FIGS.6 and 7 and only small forces can be generated tending to draw thethread into the space between the fin l9 and the resilient tongue 30.

it will be appreciated that the portion of the groove not occupied bythe tongue 30 provides a thread accommoda ting groove along the needleblade corresponding to what is referred to in the sewing machine art asthe long groove of a conventional sewing machine needle. The limb ofthread Ts which extends from the needle eye and occupies the groove 15is the thread which extends to the supply spool. The other limb Tw ofthe loop of thread through the needle eye extends to the previousstitching in the work. This limb of thread Tw finds no sheltering groovein the needle and will, therefore, be formed readily into a loop duringupstroke of the needle to encourage needle thread seizure by the sewingmachine loop taker; Depending upon the direction of feed of the workanddepending upon the direction of lateral jogging of the needle, thework limb Tw of the thread maybe wrapped in various ways around theneedle blade. The danger of accidental unthreading of the needle eye isgreatest when the work limb Tw of the thread is wrapped as shown inFIGS. 6 and 7 across the outside edge of the transverse notch 50 in theneedle blade fin 19. The location of the upper wall 53 of the notch 50above the upper wall 42 of the notch 40 in the resilient tongue-30 givesrise to the favorably shallow or obtuse angle which the work limb Tw iscaused to take in these circumstances. As a result it is practicallyimpossible for sufficient force to be generated by tension in the worklimb Tw to cause The needle of this invention, moreover, may bemanufactured conveniently without requiring vspecial tools or specialmachining operations. The groove 15 may be cut with a conventionalmilling cutter, the needle blade and resilient tongue may be fabricatedby conventional methods, and the parts may be united by sim le w ldin safter t e transverse n tche have been machined m the parts byconventiona machining operations.

Having set forth the nature of this invention, what is claimed hereinis: a

l. A s'elf-threading sewing machine needle including a shank adapted tobe clamped to the sewing machine, a cylindrical blade extending from theshank and terminating in a pointed extremity, said cylindrical bladebeing formed with a straight lengthwise groove of substantially uniformcross sectional shape defining side the thread to become wedged betweenthe tongue 30 of the tin 19 of the needle blade.

The configuration of the needle of this invention in the vicinity of theneedle eye, therefore, provides an effective deterrent to unthreading ofthe needle either by the thread inadvertently wedging between the tongueand the needle blade toward the inside or toward the outside thereof.The configuration of the needle in the vicinity of the needle eye,however, does not impose any deterrent to easy introduction of thethread downwardly between the tongue 30 and the needle blade, andtherefore, the needle of this invention provides for ready introductionof the thread with minimum chance of accidental unthreading.

walls along said needle blade, an elongate resilient tongue arrangedwith said needle blade groove and extending lengthwise of said needlefrom said pointed extremity to said shank, means securing said resilienttongue to said needle blade adjacent to said pointed extremity in aposition against one side wall of said needle blade groove, said tonguebeing formed with an in wardly open transverse notch, the side wall ofsaid needle blade against which said tongue is disposed being formedwith an outwardly open transverse notch, said notches being arranged inalignment one with the other to define a needle eye, said tongueextending deeper into said needle blade groove than the depth of saidtransverse notch in said needle blade side wall, and said transversenotch in said needle blade side wall extending toward said needle shanka distance appreciably greater than said transverse notch in saidresilient tongue.

2. A self-threading sewing machine needle as set forth in claim 1 inwhich both said lengthwise groove and said transverse notch in saidneedle blade are formed to the same depth and a recess is formed in saidlengthwise groove to accommodate said resilient tongue extending deeperthan the depth of said transverse notch in said needle blade side wall.

3. A self-threading needle as set forth in claim 1 in which the notch insaid resilient tongue and the notch in said needle blade side wall areformed with substantially coplanar lower walls, and in which theoutwardly open notch in said needle blade side wall extends in adirection lengthwise of said needle blade a distance at least twice thatof said inwardly extending notch in said resilient tongue.

4. A self-threading needle as set forth in claim 1 in which said needleblade groove occupies substantially one quadrant of the cross section ofsaid needle blade and defines said walls which diverge at substantiallyright angles to each other, and in which said resilient tongue occupiesonly a portion of said needle blade groove.

a a: e

1. A self-threading sewing machine needle including a shank adapted tobe clamped to the sewing machine, a cylindrical blade extending from theshank and terminating in a pointed extremity, said cylindrical bladebeing formed with a straight lengthwise groove of substantially uniformcross sectional shape defining side walls along said needle blade, anelongate resilient tongue arranged with said needle blade groove andextending lengthwise of said needle from said pointed extremity to saidshank, means securing said resilient tongue to said needle bladeadjacent to said pointed extremity in a position against one side wallof said needle blade groove, said tongue being formed with an inwardlyopen transverse notch, the side wall of said needle blade against whichsaid tongue is disposed being formed with an outwardly open transversenotch, said notches being arranged in alignment one with the other todefine a needle eye, said tongue extending deeper into said needle bladegroove than the depth of said transverse notch in said needLe blade sidewall, and said transverse notch in said needle blade side wall extendingtoward said needle shank a distance appreciably greater than saidtransverse notch in said resilient tongue.
 2. A self-threading sewingmachine needle as set forth in claim 1 in which both said lengthwisegroove and said transverse notch in said needle blade are formed to thesame depth and a recess is formed in said lengthwise groove toaccommodate said resilient tongue extending deeper than the depth ofsaid transverse notch in said needle blade side wall.
 3. Aself-threading needle as set forth in claim 1 in which the notch in saidresilient tongue and the notch in said needle blade side wall are formedwith substantially coplanar lower walls, and in which the outwardly opennotch in said needle blade side wall extends in a direction lengthwiseof said needle blade a distance at least twice that of said inwardlyextending notch in said resilient tongue.
 4. A self-threading needle asset forth in claim 1 in which said needle blade groove occupiessubstantially one quadrant of the cross section of said needle blade anddefines said walls which diverge at substantially right angles to eachother, and in which said resilient tongue occupies only a portion ofsaid needle blade groove.